Up until now, the weighing of fruits prior to their subsequent packaging was carried out, in the majority of cases, using balances of various degrees of accuracy and which were hand operated, which means that the corresponding personnel are kept fully occupied, the rate of throughput of the product is relatively slow and errors result in the final weight of each packaged unit of fruit. Along with this, although on a greatly reduced scale, fruits are also weighed using a process which can be referred to as being semi-automatic, in which, first of all, a pre-weighing operation or partial filling of the scale pan of the corresponding balance is carried out after which the weight is finally adjusted manually, the operator then starting to fill the scale pan until a weight is finally achieved which is the closest to the desired weight, this process suffering fundamentally from the same disadvantages as those stated above in connection with weighing done on a completely manual basis.
An automatic weighing machine for fruits is also known although it is only used on a very limited scale at present, and this carried out automatic pre-weighing using a relatively large quantity of the product to be weighed and then carries out fine adjustment of the weight in order to bring this to the desired value, this being done by rejecting or accepting the fruit which remains, but this process is very slow and leads to high costs as a result of the poor weighing performance of this machine, apart from the irregularities which occur in the desired final weight.
Finally, an automatic weighing machine is known, although it is practically unknown on the market, which in the same fashion as that discussed above, carries out pre-weighing on a large portion of the products to be weighed, to which one or several units which have been individually weighed in advance are added, and this again suffers from the disadvantages referred to above, particularly concerning the relatively low degree of accuracy of the final weight of the batch of fruit.
The improvements in automatic weighing machines for fruit and the like, constituting the object of the present invention, are characterised in that they consist of: a feed entry having various channels terminating in means for retaining the product to be weighed, and allowing it to rest there, followed by horizontal transport means arranged in sets in which each set corresponds to one of said channels, the said sets being out of phase with each other as regards their motion and carrying the corresponding product from the respective retention means to a weighing means assigned to each set and, following this, from said weighing means to vertical transport means which are also constituted by the same number of sets and channels and which carry the product, which has already been weighed, to a number of ramps which are superimposed at differing heights, which discharge into respective storage areas provided with means for discharging their content, a further ramp, located above those referred to previously, being provided for leading the rejected products (as a result of its having an inadequate weight) towards the entry into the machine, the vertical transport means having selector means which allow the product to be discharged on to the corresponding ramp, and horizontal and transverse transport means being provided below said storage areas for carrying away the product in batches of predetermined and adjustable weight. The machine also includes a processing unit and programmer which establishes the strategy to be followed starting from the desired final weight of each batch of units of the product to be weighed and taking into account the actual weight of the unit to be obtained from the machine, means linking the processing unit to the various components of the machine in order to coordinate and control the latter, particularly with regard to the selective discharge of each group of the products which have already been weighed in a particular storage area, or in the reject area, employing the selector means provided on the vertical transport means and making use of the corresponding ramp; and means for operating the various components of the machine, as well as a supporting structure for these.
The means for retaining the product can be arranged at the inside end of the channel providing the feed entry to the machine and can be made up by an arrangement of "V" shaped parallel rods which fill the width of each channel and constitute sets, present in the same number as said channels, which are limited laterally by corresponding vertical flanges in order to prevent the product, which has temporarily been retained from being discharged laterally.
Advantageously, the horizontal transport means are made up by a series of inverted "U" shaped plates which are arranged vertically and parallel to each other and constitute sets which face the feed channels and are arranged so as to match up with these, both as regards location and width, so that the plates can be situated in the free spaces existing between the retention means, the plates being linked in a swivelling fashion at their lower ends to the corresponding arms of two parallel cranks which move in synchronism to each other, and the plates having at their upper region a series of V-shaped concavities for providing consecutive support of the products to be transported from the retention means to the vertical transport means, the two end plates of each group being smooth to prevent the product being transported from falling from the side of these means.
Advantageously, the weighing means consists of a series of vertical plates which are parallel to each other, which constitute sets facing the corresponding feed channels and are located on top of transducers of the load cell type; the said plates having V-shaped concavities at their upper region with the exception of the end plates of each group, which are smooth in order to prevent lateral overflow of the product being weighed, the arrangement being such that the free spaces between each pair of said plates is in alignment with the corresponding plate of the horizontal transport means, in order to allow intercalation and mutual passage of these during the motion of the horizontal transport means; the plates of the weighing means may be provided with shock absorbing components at their upper edges, for damping down the possible vibrations of the products to be weighed to thus facilitate the weighing operation.
It is possible to provide, between the weighing means and the vertical transport means, fixed means for allowing temporary resting of the product which is being transported, these being made up by a series of vertical plates which are parallel and arranged in sets which are aligned with the corresponding feed channel, the above said plates being provided with V-shaped concavities at their upper region, with the exception of the two end plates of each set which are smooth in order to prevent the product being supported from overflowing in the transverse sense, the arrangement being such that the plates of the horizontal transport means are able to pass between each pair of the above-said plates to allow the movement of said transport means.
Advantageously, the vertical transport means are made up by two lateral endless chains mounted on corresponding guiding, driving and operating components, between which a certain number of transverse and tiltable tubular supports are provided, these having rods joined to them which lie in planes which are perpendicular to the said supports and which constitute V-shaped grids arranged in a number of sets corresponding to the number of channels and in alignment with the latter, each group, at its ends having rods which are bent towards the inside of the V in order to prevent the product being transported from falling off at the edge, this being done in such a way that the free spaces between each pair of rods is able to fit between the corresponding plates of the horizontal transport means, so that the product which has already been weighed can be deposited on the corresponding grid; and the forward portion of the vertical transport means is operated in the ascending sense, so that the product is raised to reach a position at which, following operation of pivoted parts on the guide path on which corresponding wheels of arms joined to the end of the transverse tubular support, slide a backwards deflection of the corresponding pair of arms is produced and, as a result of this, a rotation of its support is obtained thus bringing about a downwardly directed turning movement of the grid or grids, thus causing the product to fall onto the corresponding ramp, which then leads the product to the respective storage area; if the product is qualified as having been rejected, by the processing unit, it will not be discharged on to the ramps linked to the operative storage areas and will be raised to a position above these where it will be discharged on to the reject ramps, so that it will be unloaded and directed towards the entry to the machine, since, at this final upper end of the ascending path, fixed deflecting means are provided which cause all the grids to automatically be tilted downwardly after which the chains, together with the transverse supports and empty grids will continue by descending vertically, at the rear of the machine, in order to return to the starting position, where without interruption and continuously, they recommence their active ascending travel.
Preferably, the storage areas are made up in such a way that each pair of them is bordered by a common intermediate wall which is fixed and by two symmetrical movable parts, each one of which constitutes the other transverse wall and the base respectively, each storage area being closed by means of two lateral walls which are displaceable outwardly to facilitate discharge of the product having the desired final weight; this discharge operation being brough about by rotation of the movable part of the storage area, which at this precise time contains the product having the desired weight, this being brought about by the processing unit via suitable operating means, the product falling on to an endless belt of adequate width which is mounted on suitable rollers and includes operating means.
The improvement constituting the object of the present invention gives rise amongst other things, to the following advantages, the possibility of setting up the machine to obtain batches of fruit of pre-determined weight, within established limits, where products are involved which are difficult to weigh due to the presence of variations in weight between each unit and where it is not possible to divide the product (oranges, lemons, apples, etc.); the attaining of exact weights of each batch, within the pre-established tolerances starting, as has been indicated above, from products of irregular weights, the weighing and final supply of batches of fruit having pre-established weights and tolerances in a completely automatic manner and at a high rate of throughput which is much greater than that of machines and apparatuses known up until now, in other words at a high operating speed of the machine and, as a result of this, a high rate of output from the machine, a reduced reject rate of units of the product being handled, when compared to the reject rate of known machines and apparatuses, since here, the combination of units of the porduct is used in order to obtain the desired final weight; additionally it provides the possibility of regulating the final weight of each batch of units of the product prior to its subject packaging, as well as the possibility of regulating the tolerance limit of this final weight in a manner which is both easy and direct and is carried out by the actual user of the machine; additionally, the machine is simple and easily adaptable to use with conventional packaging lines (it only being necessary to provide a feed machine in front of the weighing machine and a packaging machine following the weighing machine) this being simple as the height of the entry to the machine can easily be adapted to the actual height of the feed machines present on existing production lines and, since the fruit is raised using the vertical transport means it is possible, at the same time, to feed conventional packaging machines with a resulting saving in space; additionally, the possible risk of damaging the fruits which are normally products which are fragile and delicate and easily deteriorate, is eliminated as a result of the use of the retention means, horizontal transport means and vertical transport means in the form in which they are provided on the machine, since the construction and specific arrangement, both in the absolute and relative sense, of the horizontal transport means and the weighing means prevent blows and vibrations being imparted to the product which is being weighed, leading to good weighing performance both as regards the accuracy and speed, this being greater than that present in known machines and apparatuses; furthermore, the specific fixed means for allowing temporary standing of the product which is being transported makes it possible to reduce the volume of the machine as it is not necessary to make use of cranks having relatively large dimensions which would be necessary to provide horizontal displacements needed in machines of this size; and lastly the actual constructions and arrangements of the storage areas provided in the machine avoid, firstly, the products from being knocked against each other and, secondly, allow a greater speed of discharge, which results in an increased throughput or speed of operation, which is backed up using an endless belt arranged below the said storage areas, this all leading to a greater rate of output than that obtained in the case of known machines and apparatuses.
Finally, variation can be made in the number of the following facilities: the entry feed channel, the ramps and corresponding collection means for discharging the product on to them, the storage areas for receiving and temporarily storing the product (until corresponding batches of pre-determined weights are obtained), the horizontal and transverse transport means situated below the storage areas (for discharging the above stated batches of pre-weighed products) and, finally, the means for operating the components of the machine. The number of sets of the following, and the components of each set can be varied; the retaining means for the product to be weighed, the horizontal transport means, the weighing means, the fixed means for temporarily storing the product (these may, or may not be present depending on the requirements) and the vertical transport means.